The present invention is related to a control device mounted on a vehicle such as automobile, and particularly, to a heat radiating structure of the control device mounting electronic parts with heat generation such as a coil, capacitor or the like.
Recently, a control device mounted on vehicles such as automobiles or the like have a tendency of high power and high functions. Disclosed is a control device in which electronic parts are wired to each other with low resistance wirings by forming the electronic parts such as coils, capacitors, or the like as a sub-module to realize the high power and high functions.
FIG. 5 is an exploded perspective view showing a conventional control device. As shown in FIG. 5, the conventional control device as a module comprises a control board 1 mounting circuits such as a microcomputer, a sub-module 2 mounting electronic parts such as coils 8 and capacitors on a resin case 6 including wiring layers (not shown), a housing cover 3 accommodating the control board 1 and sub-module 2, and a housing base 4. The control board 1 and sub-module 2 are electrically connected to each other and fixed mechanically with screws or the like to the housing cover 3. A heat radiation fin 16 is placed on an outside surface of the housing cover 3 and a heat radiation sheet 13 is provided between the housing cover 3 and the sub-module 2. By pressing and contacting of the electronic parts to the low elasticity heat radiation sheet 13 disposed on an inner flat surface of the housing cover 3, heat from the electronic parts is radiated to the housing cover 3.
A control device using the heat radiation sheet is disclosed in Japanese laid open patent publication No. Hei 8(1996)-203263 in which a heating element disposed on a circuit board is tightly fitted into a recess portion of a housing frame through the heat radiation sheet. On the other hand, according to an electronic control device disclosed in Japanese laid open patent publication No. 2005-12127, a lid is attached so as to cover the heating element on the circuit board and a space between the lid having a heat radiation plate and heating element is filled with a heat radiation gel material.